Japanese Stiltgrass control

ikea_gwJune 7, 2011

I have patches of Japanese stiltgrass in my front lawn. Would any of the broadleaf weed killer be effective on this? Do you have any tips on controlling them? I did one round of corn gluten in March and it seems to have helped a little but it didn't provide completely control. The stiltgrass just appeared in the last 2 weeks so they are quite young.

Acclaim Extra is labeled for control of Japanese Stiltgrass. If you are on cool-season grass, apply Acclaim Extra herbicide at the label rate; 2 applications applied 4 weeks apart. Get Acclaim Extra at your nearest John Deere Landscapes/Lesco store.

Stiltgrass is a grass and will not be affected by a broadleaf weed killer. Kill it with glyphosphate (Round-Up is one brand). It will also kill your normal grass so be careful about overspray. Some overspray is inevitable. If you have Kentucky bluegrass adjacent to the stiltgrass, then the KBG will eventually fill back in. If you have fescue then you will have to reseed in the fall. You might wait until late summer to kill the stiltgrass. That way you will not have a big bare spot.

I am going to guess that the stiltgrass is in a poorly drained area. Second guess is that you are watering more often than once per week. Stiltgrass is a swamp grass and only thrives in moist soil.

Apply Acclaim Extra now for post-emerge control, and as previously mentioned, apply pre-emerge herbicide next spring for control of Japanese Stiltgrass. Dimension herbicide will give good pre-emerge control next Spring.

dchall_san_antonio, not sure about what kind of drainage my lawn has but I don't water it at all. It however is in partial shade with tall fescue, so I can see how the soil stays fairly moist. If it were up to me, I'd not grow any grass there but the SO disagrees.

The corn gluten I used was an organic pre-emerge lawn weed treatment. It is however not 100%. Is any of the chemical stuff 100%?

Nothing is 100% effective as a preem. The reason is basic timing. A preem is effective for a certain time and then it decomposes into ineffectivness. If your weeds are sprouting while the preem is in an effective state, then you have a high probability of effectiveness. If the weeds are not ready to sprout, then you may miss the window. This year my wife wants me to apply corn gluten meal every month to help with weeds. It is a fantastic fertilizer so I have the best of all worlds working for me. Grass is very dense so that helps keep weeds out. Normally I would be fighting weeds all summer in the extremely shady back, but this year is all grass.

The problem with continually moist soil is that weed seeds need continually moist soil in order to sprout. One possible benefit there is that once all the weed seeds sprout, there are no more weed seeds.